1. Field of the Invention
This invention relates to gas compressors, and more particularly, to an integral gas compressor and internal combustion engine adapted for use on flammable gases such as natural gas.
2. Description of the Prior Art
Reciprocating gas compressors are well known in the art, and generally such compressors are powered by a separate prime mover such as an electric motor or gas powered internal combustion engine. Electric motors have a disadvantage in flammable gas applications in that they often must be of a type which is at least partially explosive proof. These types of motors are relatively expensive. A disadvantage of using an electric motor of a separate internal combustion engine for driving compressors is that the drive train must include a power transmission means such as a coupling, V-belt drive, gear drive or chain drive. The present invention solves these problems by providing a gas compressor which is integral with the internal combustion engine which drives it. Preferably, the unit is constructed by modifying a portion of the cylinders in the internal combustion engine into a gas compression section.
Conversion of portions of engines into air compressors is known in the art. For example, U.S. Pat. No. 2,133,769 to Jones discloses an engine-compressor unit with one side of a V-shaped engine being converted to an air compressor. The engine discloses a Ford V-8, but other engine makes may be used. A compressor head is installed on one bank of cylinders of the engine in place of the engine head, and intake and exhaust valves are installed in the compressor head. In this apparatus, air is drawn directly into the individual inlet valves, and there is no manifolding of the inlet. The Jones apparatus is designed for use with atmospheric air only, and does not address the problems involved with handling gases with inlet pressures above atmospheric pressure or gases which are flammable, such as natural gas. The present invention provides a integral compressor and engine specifically adapted for flammable gases including manifolding all of the valve inlets together, monitoring the oil viscosity in the crankcase to insure that the gas has not diluted the oil, and venting the crankcase so that flammable gases will not build up therein.
It is well known in the art that air compressors designed for atmospheric air are not well adapted for use with incoming gases above atmospheric pressure, and particularly are not well adapted, and may even be unsafe, for use with flammable gases. Thus, the prior art air compressor engine conversions are totally unsuitable for applications other than atmospheric air.